Message-based interactions in Enterprise Application Integration (EAI) or BusinesstoBusiness (B2B) scenarios introduce a new level of complexity, especially if the partners involved in those scenarios have different notions on how these interactions should happen. Heterogeneity not only occurs at the data level, which means that the partners use different message formats, but also on the protocol/process level, which means that an expected number and a flow of messages within an interaction step may also differ between the partners involved. It is possible for example that one partner may always expect a confirmation for messages it has sent out to other entities whereas those entities do not necessarily acknowledge all received messages. Furthermore, it is possible that a receiving partner may expect information to be sent in pieces, i.e., in several messages, whereas a sending partner will provide all necessary information within a single message and expect a single answer.